I'm going to take the nihilist position on this one. What is peace? What is justice? How can we achieve either if we can't even agree on their definitions? Justice, much like its kin morality and the right/wrong dichotomy, is an abstract and relative concept dependent upon perspective. It's not like you can isolate a molecule of justice, point at it and yell "We have it!"
Peace suffers from much the same issues. Is it simply the absence of conflict? All of humanity living in harmony and without strife? Or that of the graveyard, beyond the reach of pain, suffering, and despair? Does it even exist outside of utopian daydreams? How would we even recognize it if we encountered it?
If history has taught me anything it is that conflict begets conflict. Sometimes the ends justify the means, usually not. If both sides are fighting for their own conception of justice, is the losing side not going to be convinced that they were denied justice and thus justified in further disturbing the peace to achieve it? How does one stop this perpetual and vicious cycle?
Actions exist in reality. Actions are objective. Reducing everything to non human aspects in order to qualify them as objective is a fallacy. Moral evaluations of actions are based on harm being done. Harm can be evaluated and measured. It takes consciousness to do so, just as it does to measure anything else and communicate that measurement.
Agreed. However the motivations, justifications, and interpretations of those actions are subjective.
If it's not objective, what distinguishes it from mere opinion?
Whose morals, yours or mine? Harm suffers from the same issues with definition. What constitutes harm? Upon what objective and universal standard can it be evaluated and measured?
Indeed. Just as anything else above basic functions does. Consciousness is also the source of the disagreement over terms.